[SavantIdiot]

A bit of a grandiose article, but yeah, they actually do mess with your head. Maybe not as woo-like intensity as OP elaborates.

I did one and it took me a long time to feel anything, and suddenly I couldn't tell how big my body was, or where my limbs were: my proprioception disappeared. But that was all I got. That and a bad case of the runs because I accidentally splashed some of the water into my mouth and swallowed it.